\pgfkeys{/tikz/.cd,
	start coordinate/.initial= { 0,\vertfactor },
	start coordinate/.initial= { 0,\vertfactor },
	start coordinate/.initial= { 0,\vertfactor },
	start coordinate/.initial= { 0,\vertfactor },
	another/. style= { 0,\vertfactor } ,
	start coordinate/.initial={0,\vertfactor}{something else},
}
